Dosimetric study of thoracic esophageal carcinoma radiotherapy using RapidArc combined with active breathing coordinator
10.3760/cma.j.issn.0254-5098.2012.04.008
- VernacularTitle:RapidArc联合主动呼吸控制技术应用于胸段食管癌调强放疗的剂量学研究
- Author:
Deyin ZHAI
;
Yong YIN
;
Jinhu CHEN
;
Tonghai LIU
;
Dongping SHANG
;
Changsheng MA
;
Jie LU
- Publication Type:Journal Article
- Keywords:
Esophageal carcinoma;
Intensity modulated radiotherapy;
RapidArc;
Dosimetry;
Active breathing coordinator
- From:
Chinese Journal of Radiological Medicine and Protection
2012;32(4):364-368
- CountryChina
- Language:Chinese
-
Abstract:
Objective To compare and analyze the dosimetric characteristics of the intensity-modulated arc therapy (RapidArc) combined with active breathing coordinator (ABC) in the thoracic esophageal carcinoma radiation therapy. Methods Ten thoracic esophageal carcinoma patients undergoing radiotherapy were selected for this study.The CT simulations were performed under three breath patterns respectively:moderate deep inspiration breath-hold (mDIBH) with ABC aid; Set the trigger threshold to 80％ of the peak of the respiration curve; and free breathing (FB).Based on the corresponding CT image sets,three treatment plans were generated for each patient respectively:Arc-ABC( three small arcs),ArcFB (consisted of two coplanar full arcs) and IMRT-FB plan.The following dosimetric parameters were compared among different plans:D2％,D98％,V95,homogeneity index ( HI),conformal index ( CI ) the percentage of volume receiving dose of over x Gy (Vx),monitor unit (MU),control points and treatment time.Results The planning target volume ( PTV ) of FB was 376 cm3 which decreased to 260 cm3 after using ABC.For mDIBH and FB patients,the total lung volumes were 5964.6 cm3(35％ more than FB) and 3838.8 cm3 respectively; the heart volumes were 524.4 cm3 and 642.7 cm3 respectively. No significant difference was observed among Arc-ABC,IMRT-FB and Arc-FB in terms of D2,D98,V95,CI and HI.For Arc-ABC plans,there were significant decreases of radiation dose in total-lung's V10,V20,V30,V40 and mean lung dose ( F =4.38,5.34,4.07,3.89,4.28,P ＜0.05).Various dose decreases of heart V20,V3,V40,Dmean and spinal cord Dmax were observed,yet no statistically significant difference existed.The MUs and total control points of Arc-ABC plans were significantly lower than other plans ( F =26.86,12.56,P ＜ 0.05 ).Conclusions When thoracic esophageal carcinoma patients were treated with radiotherapy,the combined utilization of RapidArc and ABC can potentially decrease the volume of irradiated lung yet escalate the dose in target.
